<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
  function Cat(name, type, sound) {
    this.name = name;
    this.type = type;
    this.miao = function () {
      console.log(sound); // 别忘了作⽤域的链式访问规则
    }
  }
  var mimi = new Cat('咪咪', '中华⽥园喵', '喵');
  var xiaohei = new Cat('⼩⿊', '波斯喵', '猫呜');
  var ciqiu = new Cat('刺球', '⾦渐层', '咕噜噜');
  console.log(mimi);
  mimi.miao();
</script>
</body>
</html>